Data systems use communication networks to exchange data. Typically, a communication network, hereinafter called network, has transmission paths interconnecting nodes each coupled to the data systems with each node arranged to write data generated by a data system onto the network and to read data addressed to a data system off the network. Some networks are arranged such that one node may continuously write data onto the network thereby preventing other nodes from gaining access to the network. Other networks use token data that is continuously transmitted on the transmission paths to sequentially arrive at each node. The token data arrival enables a node having write data to write the write data onto the network. A problem arises in that the data traffic handling capacity of such networks are limited in that nodes are prevented from writing data onto the network until the one node ceases to write data onto the network or until each node receives the token data.